Early-stage diffuse unilateral subacute neuroretinitis: improvement of vision after photocoagulation of the worm

Causes of infectious pediatric uveitis: A review

Infectious pediatric uveitis is a rare disease that can cause severe ocular damage if not detected rapidly and treated properly. Additionally, early identification of an infection can protect the child from life-threatening systemic infection. Infectious uveitis can be congenital or acquired and may manifest as a primary ocular infection or as a reactivation. Nevertheless, publications on infectious paediatric uveitis are usually limited to a small number of patients or a case report. So far, most studies on uveitis in children have focused primarily on noninfectious uveitis, and a systematic study on infectious uveitis is lacking. In this review, we summarize the literature on infectious uveitis in pediatric populations and report on the epidemiology, pathophysiology, clinical signs, diagnostic tests, and treatment. We will describe the different possible pathogens causing uveitis in childhood by microbiological group (i.e. parasites, viruses, bacteria, and fungi). We aim to contribute to early diagnosis and management of infectious pediatric uveitis, which in turn might improve not only visual outcome, but also the general health outcome.

Subretinal gnathostomiasis: A successful focal laser photocoagulation for a living parasite

Purpose

To report a case of subretinal gnathostomiasis presenting with progressive subretinal tracts of a living parasite and successfully treated with focal laser photocoagulation.

Method

Observational case report.

Patient

A 29-year-old Thai male complained of blurred vision and floaters in his left eye for two weeks. An ocular examination showed multiple, whitish, subretinal tracks at the superotemporal retina. After 5 days of oral albendazole, a moving parasite was confirmed by multimodal retinal imaging. An immunoblotting analysis was positive for Gnathostoma species.

Result

The patient was treated by laser photocoagulation with frequency-doubled Nd:YAG laser around and over the parasite. Oral albendozole was continued and naproxen was prescribed for four weeks. His vision improved to 20/20 and the inflammation subsided completely within three months. The patient has been followed for five years without local and systemic complications.

Conclusions

Focal laser photocoagulation without systemic steroids could be a successful treatment for active subretinal gnathostomiasis with a satisfactory safety profile in a long-term follow-up.

Widefield SS-OCTA for Localization of Retinal Nematode in Diffuse Unilateral Subacute Neuroretinitis

Diffuse unilateral subacute neuroretinitis (DUSN) is a rare form of chorioretinitis caused by retinal infestation by nematode larvae. Definitive diagnosis requires visualization of a motile nematode, but this can be challenging because the nematode is small, translucent, and usually motionless with overlying media opacity from cellular inflammation. The authors describe a case of DUSN in which widefield swept-source optical coherence tomography angiography was used to localize a midperipheral intraretinal nematode facilitating subsequent clinical observation of movement. Inflammation resolved after focal laser photocoagulation of the nematode with recovery of visual acuity to 20/20. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:345-349.].

Diffuse unilateral subacute neuroretinitis: review article

Diffuse unilateral subacute neuroretinitis (DUSN) is an ocular infectious disease that can lead to severe visual impairment and blindness. It usually occurs in healthy young individuals and depending on the stage of the disease, it may present as vitritis, multifocal gray-white lesions in the outer retina, and derangement of the retinal pigment epithelium, narrowing of the retinal vessels and optic atrophy. Parasites of different sizes and species have been proposed as the etiologic agent of DUSN, including Ancylostoma caninum, Toxocara canis, and others. Thus, it is hypothesized that different infectious worms may be considered as the likely cause of both an autoimmune and toxic form of nematode retinopathy. Because serologic testing is variable, the definitive diagnosis is made when clinical characteristics of DUSN are found in conjunction with an intraocular worm. Ancillary tests can assist in the differential diagnosis when the nematode cannot be visualized, such as fluorescein and indocyanine green angiography, electrophysiological tests, visual field studies, and more recently, optical coherence tomography angiography. Cases in which the worm can be identified, it is defined as confirmed DUSN, and eyes with the typical clinical features but without identification of the worm should be classified as presumed DUSN. In confirmed DUSN, the classic treatment is directly photocoagulation of the worm; however, it can only be visualized in 30% (to 40%) of cases. Treatment of presumed DUSN cases with high-dose oral albendazole has shown encouraging results. However, perhaps due to the disease’s rarity or its underdiagnosis, there are no studies comparing current treatment modalities in both presumed and confirmed DUSN. Due to the possibility of this disease being, in part, autoimmune nematode retinopathy, corticosteroids associated with both albendazole or laser therapy, could be in any way beneficial. Thus, further comparative studies are necessary to elucidate the best treatment for this potentially blinding disease.

Diffuse Unilateral Subacute Neuroretinitis Evolving With Submacular Granuloma

DUSN is an infectious ocular disease that can lead to severe visual impairment and blindness. It usually occurs in young healthy individuals and depending on the stage of the disease, clinical presentation may range from mild vitritis and multifocal gray-white lesions in outer retina to optic atrophy.Parasites of different sizes and species have been proposed as the etiological agent of this disease. Thus, it is hypothesized that different infectious worms may be considered as the likely cause of a both autoimmune and toxic form of nematode retinopathy.Most patients present with already severe visual impairment and in the later stages of the disease, where the likelihood of improvement is low, despite therapy. In cases of early diagnosis, prompt treatment, whether with oral antihelmintic or direct photocoagulation of the worm, patients may show considerable visual improvement and have a more favorable prognosis.

Optical coherence tomography angiography of diffuse unilateral subacute neuroretinitis

Purpose

Diffuse unilateral subacute neuroretinitis (DUSN) is often a challenging diagnosis to make. We present a DUSN case with its multimodal imaging to aid in the diagnosis, emphasizing the observations on optical coherence tomography angiography (OCTA).

Observations

The evolution of a DUSN case is presented. Fundus photography and OCTA aided in the identification of the nematode.

Conclusions and importance

DUSN is a difficult diagnosis to establish. We report the first case to our knowledge in which OCTA aided in the diagnosis of DUSN.

Diffuse Unilateral Subacute Neuroretinitis From Raccoon Exposure Resistant to Laser Photocoagulation

Diffuse unilateral subacute neuroretinitis (DUSN) is an ocular disease caused by a subretinal nematode worm. The authors present a unique case of a 9-year-old girl with DUSN due to presumed Baylisascaris procyonis, given the size of the worm and previous raccoon exposure. The worm was located in the inner retina and treated with laser photocoagulation and albendazole. At the 1-week follow-up, the worm was still mobile despite being inactive immediately after the initial laser treatment and required a more prolonged laser session. This case serves to highlight the importance of close follow-up in patients with DUSN to ensure the worm is inactivated. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:686-690.].

Clinical experience in treatment of diffuse unilateral subretinal neuroretinitis

Purpose

To describe the clinical features, management, and outcomes of patients with diffuse unilateral subacute neuroretinitis (DUSN).

Methods

A noncomparative, consecutive analysis of case series from two tertiary care campuses of LV Prasad Eye Institute, India, between January 2011 and April 2014 was performed. Medical records of the patients presenting with DUSN (early or late stage) were reviewed.

Results

The current study included 13 patients. The majority (10/13, 76.92%) of the patients were aged 20 years or less. All patients had unilateral eye involvement. Visual acuity at presentation was 20/200 or worse in 9/13 (69.23%) patients. A delay in diagnosis occurred in 6/13 patients, and initial diagnosis in these patients included retinitis pigmentosa (4 patients) and posterior uveitis (2 patients). Clinical features included early presentation (prominent vitritis, localized retinitis, and vasculitis) in 7/13 (53.85%) patients and late presentation (attenuation of vessels, retinal pigment epithelium atrophic changes, and optic atrophy) in 6/13 (46.15%) patients. Worm could not be identified in any of the cases. All the patients received laser photocoagulation of retina and oral albendazole treatment for a period of 30 days. With treatment, visual acuity improved in seven patients (six early stage, one late stage) and remained unchanged in six patients. Mean follow-up period was 8.69 months (range, 1–21 months). The mean central foveal thickness in the affected eye, done by optical coherence tomography, during the late stage of the disease was 188.20±40 µm (range, 111–242 µm), which was significantly thinner than the fellow eye, 238.70±36.90 µm (range, 186–319 µm), P=0.008.

Conclusion

DUSN is a serious vision threatening disease, which may progress to profound vision loss in the later stage of the disease. Visualization of subretinal worm is usually not possible. Treatment with high-dose albendazole therapy and laser photocoagulation may alter the blood–retinal barrier and may be useful in achieving visual recovery.

Diffuse unilateral subacute neuroretinitis in a healthy Korean male: the first case report in Korea

A 52-yr-old male was referred for progressive visual loss in the left eye. The decimal best-corrected visual acuity (BCVA) was 0.01. Fundus examination revealed diffuse retinal pigment epithelial degeneration, focal yellow-white, infiltrative subretinal lesion with fuzzy border and a live nematode within the retina. Diffuse unilateral subacute neuroretinitis (DUSN) was diagnosed and the direct laser photocoagulation was performed to destroy the live nematode. During eight months after treatment, BCVA gradually improved to 0.2 along with the gradual restoration of outer retinal layers on SD-OCT. We report on the first case of DUSN in Korea. DUSN should be included in the differential diagnosis of unexplained unilateral visual loss in otherwise healthy subjects.

Diffuse unilateral subacute neuroretinitis

Diffuse unilateral subacute neuroretinitis (DUSN) is a usually unilateral inflammatory disease characterized by an insidious, usually severe loss of peripheral and central vision. Clinical characteristics are manifested in early and late stages. Parasites of different sizes and several species of nematodes have been reported as the etiology of DUSN without conclusive evidence about the specific agent. Because serologic testing has been variable, the definitive diagnosis is made when the clinical characteristics of DUSN are found in conjunction with an intraocular worm. Laser photocoagulation, pars plana vitrectomy, thiabendazole, and albendazole have been used to treat DUSN with variable success.

Clinical features of 121 patients with diffuse unilateral subacute neuroretinitis

PURPOSE

To describe the determinant clinical signs to diagnose diffuse unilateral subacute neuroretinitis (DUSN) and the main features related to identification of the live worm.

DESIGN

Retrospective study performed at the Federal University of Rio Grande do Norte, Rio Grande do Norte, Brazil, between 2003 and 2008.

METHODS

Patients with early- or late-stage diffuse unilateral subacute neuroretinitis were included. All patients underwent complete ophthalmologic examination and had a minimum of 6 months of follow-up.

RESULTS

A total of 121 patients were included. Most patients were younger than 20 years (69.42%). Visual acuity was 20/400 or worse in 86 patients (71.7%). Nine patients (7.43%) presented in the early stage and 112 (92.57%) patients presented in the late stage. Subretinal tracks (91.7%), focal alterations of the retinal pigment epithelium (89.3%), small white spots (80.2%), and optic nerve atrophy (76.9%) were the most frequent clinical features. The subretinal worm was identified in 48 patients (39.66%), and laser treatment to destroy it was performed in all cases. The most common location of the nematode was the posterior pole (21 patients). It was observed that the younger the age, the higher the indices of larvae identification (P=.022). Multifocal yellow-white lesions and vitritis were correlated with identification of the worm (P=.001). Mean logarithm of the minimal angle of resolution visual acuity was 1.466 (20/600) and 1.281 (20/400) before and after laser treatment, respectively (P<.005).

CONCLUSIONS

Identification of clinical signs and diagnosis of diffuse unilateral subacute neuroretinitis in its early stage, followed by prompt location and destruction of the worm by photocoagulation, may improve the vision of affected patients.

Spectral domain optical coherence tomography in diffuse unilateral subacute neuroretinitis

Purpose. To describe the SD-OCT findings in patients with diffuse unilateral subacute neuroretinitis (DUSN) and evaluate CRT and RNFL thickness. Methods. Patients with clinical diagnosis of DUSN who were submitted to SD-OCT were included in the study. Complete ophthalmologic examination and SD-OCT were performed. Cirrus scan strategy protocols used were 200 × 200 macular cube, optic nerve head cube, and HD-5 line raster. Results. Eight patients with DUSN were included. Mean RNFL thickness was 80.25 μm and 104.75 μm for affected and normal eyes, respectively. Late stage had mean RNFL thickness of 74.83 μm compared to 96.5 μm in early stage. Mean CMT was 205.5 μm for affected eyes and 255.13 μm for normal fellow eyes. Conclusion. RNFL and CMT were thinner in DUSN eyes compared to normal eyes. Late-stage disease had more pronounced thinning compared to early-stage patients. This thinning in RNFL and CMT may reflect the low visual acuity in patients with DUSN.

Subretinal worm and repeat laser photocoagulation

Diffuse unilateral subacute neuroretinitis (DUSN) can be a diagnostic dilemma. Laser photocoagulation of the subretinal worm is an effective treatment for eradication. Early laser photocoagulation has been advocated. We report a case of a middle aged man who presented with decreased vision and a sub retinal macular worm that required two laser sessions for complete eradication of the worm.

Ocular parasitic diseases: a review on toxocariasis and diffuse unilateral subacute neuroretinitis

Parasitic infections may damage various ocular tissues, thereby causing visual dysfunction. In 1950, Wilder described the first case in which larval forms of nematodal intestinal roundworms (Ascaridoidea: Ascaris, Toxocara, Ancylostoma, Necator, and Strongyloides) were implicated as a cause of intraocular disease. This review focuses on two disorders associated with parasitic infections: ocular toxocariasis and diffuse unilateral subacute neuroretinitis.

Intraocular nematode with diffuse unilateral subacute neuroretinitis: case report

Background

Live intraocular nematode is a rare occurrence. Nematode can migrate actively within the eye, creating visual symptoms and damaging ocular tissue.

Case presentation

A 26-year old man presented with painless reduced vision of the left eye for one week duration. It was associated with floaters. Visual acuity on the left eye was hand movement. Anterior segment examination was normal with normal intra-ocular pressure. Fundus examination showed a live nematode lying subretinally at the macular area with macular oedema and multifocal chorioretinal lesions at peripheral retina. There was no vitritis, vasculitis or any retinal hemorrhage. Systemic examination revealed normal findings and laboratory studies only showed leucocytosis with normal eosinophil count and negative serum toxocara antibody. The diagnosis of introcular nematode with diffuse unilateral subacute neuroretinitis was made. He was treated with oral anti-helminths and a course of oral steroid at a reducing dose. The nematode had died evidenced by its immobility during the treatment and finally disintegrated, leaving macular oedema with mottling appearance and mild hyperpigmentation. Multifocal chorioretinal lesions had also resolved. However despite treatment his visual acuity during follow-up had remained poor.

Conclusions

Cases of intraocular nematode, though not commonly encountered, continue to present the ophthalmologist with the problem of diagnosis and management and hence poorer prognosis to the patient.

Zoonotic helminths affecting the human eye

Nowaday, zoonoses are an important cause of human parasitic diseases worldwide and a major threat to the socio-economic development, mainly in developing countries. Importantly, zoonotic helminths that affect human eyes (HIE) may cause blindness with severe socio-economic consequences to human communities. These infections include nematodes, cestodes and trematodes, which may be transmitted by vectors (dirofilariasis, onchocerciasis, thelaziasis), food consumption (sparganosis, trichinellosis) and those acquired indirectly from the environment (ascariasis, echinococcosis, fascioliasis). Adult and/or larval stages of HIE may localize into human ocular tissues externally (i.e., lachrymal glands, eyelids, conjunctival sacs) or into the ocular globe (i.e., intravitreous retina, anterior and or posterior chamber) causing symptoms due to the parasitic localization in the eyes or to the immune reaction they elicit in the host. Unfortunately, data on HIE are scant and mostly limited to case reports from different countries. The biology and epidemiology of the most frequently reported HIE are discussed as well as clinical description of the diseases, diagnostic considerations and video clips on their presentation and surgical treatment.

Diffuse unilateral subacute neuroretinitis

BACKGROUND

In patients with diffuse unilateral subacute neuroretinitis (DUSN), the presence and, therefore, clinical visualization of subretinal nematode makes the diagnosis obvious. However when located under the retinal pigment epithelium (RPE), diagnosis is presumptive and challenging. We report a case of presumed DUSN to illustrate this diagnostic dilemma and to highlight the clinical signs which suggest the diagnosis.

METHODS

Case report of a patient with DUSN.

RESULTS

In our patient the nematode was not located subretinally and this made the diagnosis difficult. However, the appearance of sub-RPE serpiginous tract in the infero-temporal retina, peripheral RPE hypopigmentation and good clinical response to anti-helminthics supported the diagnosis.

CONCLUSIONS

It is important to have a high index of suspicion when patients present with a combination of above findings. This will help in early control of ocular inflammation and salvaging vision.

Diffuse unilateral subacute neuroretinitis: report of a case from the Indian subcontinent and the importance of immediate photocoagulation

PURPOSE

To report a case of DUSN from the Indian subcontinent and emphasize the importance of immediate photocoagulation.

METHOD

Review of case record.

RESULT

The referring ophthalmologist had photographed the subretinal worm but had not undertaken laser photocoagulation. On presentation to us the patient had features typical of DUSN but no worm could be detected despite repeated examinations. Failure to localize the worm at subsequent examinations resulted in only partial recovery of vision.

CONCLUSION

Whenever the nematode is detected, immediate laser photocoagulation of the worm is necessary as the migratory worm may be difficult to identify later on. This is necessary to prevent the otherwise natural decline in vision.

Diffuse unilateral subacute neuroretinitis with unusual findings

PURPOSE

To report two cases of diffuse unilateral subacute neuroretinitis (DUSN) with unusual findings.

DESIGN

Observational and interventional case series.

METHODS

Two patients with DUSN were found to have the unusual findings of a large live worm in one eye and macular cyst in the other. Both patients underwent fundus fluorescein angiography and optical coherence tomography.

RESULTS

Photocoagulation to the worm was performed in one patient; the other received a course of oral albendazole. Both remained stable over six months of follow-up.

CONCLUSIONS

We report a case of DUSN due to a worm, the large size of which suggests it to be different from the usual reported causative agents. We also report macular cyst as an associated finding in DUSN.